STORY ARCHIVE

Salt Man

Salinity is the biggest environmental problem facing Australia, and scientists are struggling to find ways to solve it. But maybe they’re just not thinking far enough outside the square. Why not remove the salt from the ground and sell it to yuppies to sprinkle on their dinner? It may sound like a joke but Duncan Thomson is actually doing it. He is also extracting other valuable chemicals from our salty land and selling them, from fertilisers to road-building materials. He says he’s turning salinity from a negative into a positive.

TRANSCRIPT

Narration: Salinity is the biggest environmental problem facing Australia. Salt’s coming out of the ground and degrading millions of hectares of farmland, and there’s salty water getting into our rivers. Scientists are struggling to find ways to stop it.

But maybe they’re just not thinking far enough outside the square.

Narration: Why not package up the salt and convince yuppies to sprinkle it on their dinner. That’s what a Mildura man’s done. He’s extracted the salt from the groundwater in the Murray Darling Basin and turned it into a gourmet product.

Narration: This is the Mildura factory where the table salt’s manufactured. And the man with this novel salinity solution is Duncan Thomson. He works salt, breathes salt and sleeps in his salt factory.

Narration: What got Duncan is, we have a salinity problem yet we import salt from overseas.

Duncan Thomson: : It is – it seems ironic but quite a few multi thousands of tonnes are being imported. There’s salt coming in from Thailand – there’s salt coming in from England all the time.

Narration: And this sodium chloride is not just for eating.

Duncan Thomson: The sodium chloride is used in a lot areas – all the chlorines salt – your hydrochloric salt – swimming pool salt of course then we put out salt for the hide industry – for curing…..

Graham: So you do all that stuff from the stuff you’re mining here?

Narration: So Duncan starting harvesting and selling the salt from our salinity-affected Murray Darling. And he thinks there’s a valuable lesson here – to solve the salinity problem we’ve got to stop thinking of it as a negative.

Duncan Thomson: Salinity being the issue it is nowadays, I think it’s just to turn that negative into a positive and once you get to that positive thing you – things are created from positives never a negative.”

Narration: With his positive thinking, and a little help from his partners at CSIRO, he’s come up with another way of turning salinity into a plus. It turns out there are also valuable chemicals hiding in our salt-effected land.

Dr Hal Aral: The underground salts in the Murray Basin they are really rich – much richer than sea water – with respect to magnesium and sulphate and that was quite exciting.

Narration: CSIRO’s Hal Aral believes there are many other useful chemicals too, from fertilisers to road-building materials. It’s just a matter of working out ways to extract them.

To see how to do that, you first need to know how Duncan gets the salt out of the Murray-Darling groundwater. It all starts with a pump that was put in to stop the groundwater getting into the river.

Leighton Schmidt: Well this is one of the underground submersible pumps that pumps the water from the underground aquifer, it’s a saline aquifer, it’s about 30 metres below us. If we don’t pump the water out that then flows back out to the Murray River and then the Murray River becomes saline and then the people down in South Australia…

G: they have to drink the salty water.

Narration: A few kilometres back from the river the pump just empties out over the ground, creating a system of artificial lakes.

Leighton Schmidt: So it’s a huge lake system. What it does is it takes the saline water here and gradually evaporates it. So the further you get north on the lake system the higher the concentration.

Narration: The far end of the lake is highly saline. There the liquid’s pumped off and the salt is harvested. But it’s that pumped off liquid that the CSIRO was interested in. It’s called bittern

Dr Christian Doblin: Bittern is a saline solution which has had the sodium chloride extracted from it and this is what’s left behind.

Narration: It turns out Duncan’s bittern is rich in magnesium sulphate, or Epson salts…a widely used fertiliser. And the chemical can be extracted by refrigeration.

Dr Christian Doblin: Now we’re cooling this solution, and in the process of cooling it we will crystallise out magnesium sulphate.

Narration: The key is to cool it at just the right rate.

Dr Hal Aral: This thing is not really rocket science - if you take your bittern and put it into the fridge, next morning you will see a crystal, but really the expertise is how can you make that really pure product.

Narration: Twenty minutes later and after the bittern has been cooled to five degrees Celsius, the pure Epsom salts crystallise out. The process was scaled up and Duncan now has an Epsom salts factory. But there’s even more money in this salt-affected land. The liquid left over after the Epsom salts that has been removed is rich in magnesium chloride. Duncan sells that to be sprayed on dirt roads, to harden up the surface and suppress the dust. Back at the gourmet salt factory Duncan’s just got his first order from overseas.

Duncan Thomson: So we’re selling something and our salt problem is going out of the area.

Graham: So you’re exporting the salt problem.

Narration: Duncan seems set to turn salinity into a financial success.

Dr Hal Aral: He will make money yeah.

Dr Christian Doblin: Yeah he should – he should make money out of it. We hope so – we want another project out of him.

Narration: But will Duncan’s chemicals and yuppie fish and chip salt help the environment? Has he got the salinity problem licked?

Duncan Thomson: I think we’re a strong link in the chain. The unfortunate part is that Australia uses about a million tones internally per year and I think there’s several million tones have to be removed from the Murray Darling Basin to really have a major effect on the Murray River and…